The invention relates to an optical device for measuring the displacement velocity of a first moving element with respect to a second element, the device being fixed to one of the two elements and comprising:                means for emitting at least one incident light beam in the direction of the other element,        means for receiving the light scattered by the other element, comprising front and rear detection means arranged substantially perpendicularly to one another,        processing means, connected to the front and rear detection means and comprising means for determining the longitudinal and/or transverse displacement velocity of the moving element.        